This invention relates to a vacuum cleaner and to a suction changeover valve for the vacuum cleaner.
Known vacuum cleaners are either of the so-called upright type or the so-called cylinder type. Upright vacuum cleaners comprise an upright body pivotally connected at its lower end to a wheeled floor-engaging unit for partial rotation forwardly and rearwardly about a transverse axis. The upright body encloses a motor/fan unit which develops suction for drawing air through an inlet in the floor-engaging unit of the cleaner and then through a dust separation device. A handle is provided at the upper end of the upright body for manoeuvring the cleaner. A motor-driven, rotary agitator brush is mounted across the inlet in the floor-engaging unit to beat and sweep the floor in the region of the airflow into the cleaner.
Cylinder vacuum cleaners comprise a body which encloses a motor/fan unit which draws air into a dust separation device though an elongate flexible hose. A plurality of tools are provided for fitting to the end of the hose.
Upright vacuum cleaners are better at cleaning carpets than cylinder vacuum cleaners because of the action of the rotating agitator brush. However, cylinder vacuum cleaners are better suited for above-floor cleaning and for cleaning in places where an upright cleaner cannot be used.
In order to provide a cleaner having the advantages of both upright and cylinder cleaners, it is known to provide an upright cleaner having an elongate flexible hose, the inlet of which can either be connected to the floor-engaging unit of the cleaner for conventional floor cleaning, or connected to an extension tube and/or cleaning tools for above-floor cleaning.
A disadvantage of this arrangement is that during conventional floor cleaning, the airflow though the cleaner is partially restricted by the elongate flexible hose, which is coiled for storage on the back of the cleaner. The coiled length of hose is also susceptible to blockage.
In order to overcome the above-mentioned problem, vacuum cleaners of the upright type are known which comprise a hose and a valve which can be actuated such that the suction is either applied to the hose for above-floor cleaning or to the floor-engaging unit of the cleaner for conventional floor cleaning.
European Patent No. 1,121,043 discloses an upright cyclonic vacuum cleaner of the above-mentioned type, comprising an elongate rigid tube, which is mounted vertically to the rear of the cleaner body and which forms a handle for manoeuvring the cleaner during conventional floor cleaning. The cyclonic separator is connected to the outlet of a first member of a two-way valve. The valve further comprises a second valve member having a first inlet port connected to the air inlet on the underside of the floor-engaging unit and a second inlet port connected to the elongate rigid tube.
The valve is arranged to connect the cyclonic separator to the air inlet on the underside of the floor-engaging unit when the upright body of the cleaner is pivoted rearwardly relative to the floor-engaging unit of the cleaner. In order to carry out above-floor cleaning, the upright body of the cleaner is pivoted forwardly into its upright position relative to the floor-engaging unit of the cleaner, to divert the suction airstream from the floor-engaging unit of the cleaner to the elongate rigid tube.
The outlet port of the first member of the valve is provided with a resilient seal. Wear and potential damage to the seal due to sliding contact with the second valve member is eliminated by providing a cam-and-follower mechanism whereby the seal is disposed out of sliding contact with the second valve member during changeover movements. This mechanism adds to the complexity of the valve.
U.S. Pat. No. 5,732,439 discloses a valve comprising a flap, which is responsive to the attitude of the cleaner handle (whether rearwardly inclined for floor cleaning, or upright for above-floor cleaning) to route the suction airstream to the separator unit from one or other of two inlets. The valve comprises a pivoted flap located in a chamber to which the separator inlet duct, and dirty air ducts from the floor nozzle and hose respectively, are connected. Dependent on the momentary position of the flap, one of the dirty air inlets is blocked whilst the other dirty air inlet remains open. The valve responds to a change in attitude of the cleaner handle, between upright and inclined positions, to switch the dirty air path from one dirty air inlet to the other. The mechanism required to effect reliable operation of such valve arrangements, with acceptable levels of sealing, is relatively complex, involving cams, springs and linkages to actuate the flap.
Alternative actuating mechanisms for changeover flap valves are known whereby removal of above-floor cleaning apparatus from its stored position on the body of the cleaner gives rise to switching of the valve. Such an arrangement is disclosed in United Kingdom Patent No. 2,291,336. Manually operable valves are also known.